The game functions like chess, with 2 notable exceptions :
Pieces taken from your opponent can be reused and placed (almost) anywhere on the board in place of moving a piece inside the board (that is why they have a directional shape and are all the same color). It is also allowed to check-mate your opponent by dropping a piece on the board (except with a pawn, for some obscure reason).
Most pieces have a promotion, a bit like the pawn turns into a queen when reaching the last row. In Shogi, pieces are promoted when making a move on the board that enters, leaves or moves inside the last 3 rows opposite to you (your opponent's camp). The Rook gains the ability to move 1 square diagonally (x shape) and the Bishop gains the ability to move 1 adjacent square (+ shape). The other lesser pieces convert to a Gold General. Only the King and the Gold General cannot be promoted.
The concept of dropping pieces taken from the opponents exists in a 4 player variant of persian chess where 2 teams of 2 play each other, each team has a black and a white player, and anything taken by the white player from their black opponent is given to their black teammate, who can use it on their own board, and vice versa.